Thin film materials such as ceramic superconductors, ferroelectrics, and synthetic diamond have significant applications in microelectronics, microoptics, and microdynamics. Polycrystalline diamond thin films, for example, offer a combination of highly desirable physical properties, including hardness, chemical inertness, transparency to light from the ultraviolet to the far infrared region, and resistance to laser damage. Synthetic diamond films, however, can be formed only under high temperature processing conditions. Furthermore, high temperature plasma and filament chemical vapor deposition (CVD) processes produce diamond films that have large average grain size and many defects in the faceted crystals. In many applications, the optical and frictional characteristics of such diamond films are limited by the surface roughness produced by conventional deposition techniques. This roughness causes optical scattering from the visible range through the long wavelength infrared region. Large grains also provide a film that is too abrasive for direct use as a bearing surface for wear reduction. Methods exist for post-deposition polishing of polycrystalline diamond surfaces, but the large, irregular grain size of typical diamond films makes polishing difficult.
In many applications of diamond films it is desirable to provide a dense, uniform, fine-grained microstructure that has good optical characteristics and is amenable to post-deposition surface polishing. The fabrication of such diamond films, which may include microscale patterning for purposes of nucleation control, surface relief, and adhesion improvement, generally requires various masking, etching, deposition, and resist removal steps at temperatures that exceed the capabilities of commonly used photoresist materials. Because conventional polymeric resist materials tend to flow, glassify, carbonize, or crack if used above their maximum operating temperatures, they are unsatisfactory for high temperature microlithographic process steps. Thus, there is a need for microlithographic patterning techniques that provide high temperature processing capability, diamond nucleation control, and production of high quality, fine-grained diamond films, including microstructures and surface relief features.